A few weeks ago, I reported a new (for me) species of milkweed bug.
Here are two photographs of the more familiar Large Milkweed Bug, Oncopeltus fasciatus, from the archives.
Most members of the group feed on seeds, and Large Milkweed Bugs prefer the seeds of milkweeds.
They also feed on the milkweed plant when there are no seeds available. The ones in the photographs are sitting on the flower buds of a butterfly milkweed.
As you might guess from the bright red and black warning coloration, milkweed bugs take up the same toxins from milkweeds as the monarch caterpillar does. Their colors say, "Don't eat me!"
Surprisingly, Large Milkweed Bugs are commonly used for science experiments because they are fairly easy to take care of. If you don't have milkweed seeds, they will feed on raw sunflower seeds as well as some nuts. They also need a good source of water.
Illinois.edu has more information and detailed rearing instructions.